Node.js: Difference between req.query[] and req.params

Given this route

app.get('/hi/:param1', function(req,res){} );
// regex version
app.get(/^\/hi\/(.*)$/, function(req,res){} );
// unnamed wild card
app.get('/hi/*', function(req,res){} );

and given this URL http://www.google.com/hi/there?qs1=you&qs2=tube

You will have:

req.query

{
  qs1: 'you',
  qs2: 'tube'
}

req.params

{
  param1: 'there'
}

When you use a regular expression for the route definition, capture groups are provided in the array using req.params[n], where n is the nth capture group. This rule is applied to unnamed wild card matches with string routes

Express req.params >>

Suppose you have defined your route name like this:

https://localhost:3000/user/:userId

which will become:

https://localhost:3000/user/5896544

Here, if you will print: request.params

{
userId : 5896544
}

so

request.params.userId = 5896544

so request.params is an object containing properties to the named route

and request.query comes from query parameters in the URL eg:

https://localhost:3000/user?userId=5896544 

request.query

{

userId: 5896544

}

so

request.query.userId = 5896544

req.params contains route parameters (in the path portion of the URL), and req.query contains the URL query parameters (after the ? in the URL).

You can also use req.param(name) to look up a parameter in both places (as well as req.body), but this method is now deprecated.